Fig. 3. Patterning of the pre-implantation embryo progresses through an initial phase of high variability. Oct4 (A), Cdx2 (B) and Nanog (C) distribution at defined stages of development. For every embryo, the counterstained DNA is shown in the row below. White and green arrowheads indicate nuclei of interest of inside and outside cells, respectively. Actin (red) marks the cell membranes. Asterisks indicate blastomeres with only minimal contact to the outside. Images are single optical sections, except for those at 0 hp-c, being maximum intensity projections. Scale bar: 20 µm.